研究了9种有机溶剂对Eu3+、Tb3+、Dy3+三种稀土离子与异乳清酸的配位反应后所发射的特征荧光的强度,结果发现1,2-丙二醇的增敏效果最显著.在此基础上提出了荧光分光光度法测定上述3种稀土元素的方法,并对有机溶剂对荧光强度的增敏作用的机理作了探讨.试验的最佳条件为:在pH 8.0的氨性缓冲介质中并含有40%(体积分数) 1,2-丙二醇和7.0×10-4mol·L-1异乳清酸.试验结果:Eu3+、Tb3+、Dy3+的激发波长均为300 nm,发射波长分别为612,544,574 nm,线性范围分别为0.60~8.00,0.000 5~3.00,0.20~7.00 mg·L-1;检出限分别为0.56,5.3×10-4,0.18 mg·L-1;用标准加入法做回收率试验,结果在95.6%~109.3%之间.

It was found that among 9 kinds of organic solvents tested,1,2-propanediol showed the most remarkable sensitization effect on the fluorescence intensity of the coordination complexes formed between iso-orotic acid and europium(Ⅲ),terbium(Ⅲ) or dysprosium(Ⅲ). Based on these phenomena,new methods for the fluorospectrophotometric determination of Eu(Ⅲ),Tb(Ⅲ) or Dy(Ⅲ) were proposed and the mechanism of the sensitization effect of the organic solvents was discussed. The fluorescence reaction of either of the 3 rare earth elements with iso-orotic acid was carried out in a solution of ammoniacal buffer (pH 8.0),containing 40% (by volume) of 1,2-propanediol and 7.0×10-4mol·L-1 iso-orotic acid,and the following results were obtained for Eu(Ⅲ),Tb(Ⅲ) and Dy(Ⅲ) respectively: wavelength of excitaction 300 nm,wavelength of emission 612,544,574 nm,range of linearity 0.60-8.00,0.000 5-3.00,0.20-7.00 mg·L-1,detection limits 0.56,5.3×10-4,0.18 mg·L-1. In the test for recovery by the standard addition method,values of recovery obtained were in the range of 95.6%-109.3%.